What is Takt Time? Defining and Using
What is Takt Time?
Tact time is the drum beat to which our organization should operate, based on the German word for metronome (like an inverted pendulum used for keeping time in music.) It is the basis on which we can create flow within our work-cells and throughout our whole value chain from raw materials to customer delivery.
Tact time is the available working time for production divided by the actual average daily demand for our product(s) expressed in minutes. this gives us the customer demand rate for use throughout our organization and the supply chain.
The Takt time also forms the basis for enabling the design and balancing of our work-cells and production lines in an efficient manner.
Many companies just try to rush as fast as they can thinking if they are producing as quickly as they can then they must be efficient. However a company only has to produce as fast as the customer requires it to.
Why is Takt Time Important?
The Takt time is the demand rate through your process or even the whole value chain. If you cannot ensure that each process can meet the demand rate then you will not be able to keep up with customer demand.
Alternatively if your process produces far faster than the Takt time then you will either make far faster than the customer requires creating excessive stock or you will be using equipment highly inefficiently.
Each step in your process should be producing at or just below the takt time.
Using Takt time
Takt Time vs Cycle Time
Takt time should not be confused with machine cycle time; machine cycle time is the time taken to produce a part, this could exceed takt time in some cases which would mean that the process would be incapable of producing enough products within the available time.
Where cycle times exceed your Takt time there is a need for machines to either be run on additional shifts to build stock, the product to be outsourced or a need for additional machines to be run in parallel.
Calculating Takt Time
Tact Time Calculation
Calculating the takt time is a simple enough process; firstly we need the available working time for the working day. This is the total number of minutes less any time put aside for things such as team briefings, breaks and planned maintenance. So if the working day is two eight hour shifts each with 40 minutes of breaks, 10 minutes of team briefing, and 10 minutes of planned maintenance our available time is; (480 – 40 – 10 -10) x 2 shifts = 840 minutes
Our average demand is the number of parts require on average for each day, say for instance 1680 parts each and every day.
Our takt time then become Available time / average demand = 840 / 1680 = 0.5 Minutes or 30 seconds. This means that we have to produce one part every 30 seconds to keep up with customer demand.
TAKT Time Calculation Example
Takt time video
What is Pitch Time
In some industries rather than use the Takt time for their customer demand rate they use the Pitch rate, which is the Takt time multiplied by the number of components contained in their standard container. Pitch time and Takt time can be used in exactly the same way for analyzing and balancing work flows within your work cells.
Using Takt Time
Because the Takt time is a measure of how many parts the customer wants each minute we can use this to balance each process step to produce exactly at the rate of demand. We do this by balancing the work elements of each process step, enabling work to be shared in a manner that will minimize waiting time for each operator.
So for instance if our takt time is 30 seconds and operator A has work that takes 40 seconds and B has only 15 seconds of work; A has too much work to do and B will be waiting for A as they have less work to do. We can allocate some of operator A’s work to operator B to bring his work load below the 30 second takt time and maintain customer demand.
It also highlights machine cycles that are over the takt time, these machines will either have to be duplicated or run on overtime and stock kept to enable the process to match customer demand.
Machines that run faster than takt time should be slowed down, this may sound like it will cost you more but it will dramatically reduce inventory and all of the associated costs with moving and storing that inventory.
Inventory is the biggest of the 7 lean wastes and should be avoided at all costs, not only does it tie up your cash it also costs you with regards to handling and storage and hides many other issues such as quality problems.
Yamazumi and Takt
Yamazumi boards and Takt time
Yamazumi boards are a simple way to visualize the work content of specific jobs and compare them to the takt time for the process. They are also useful in highlighting wasteful steps in the process to keep the focus on eliminating waste.
Activity timing is made of each work element and these are placed on the yamazumi board as a stacked bar chart for each operator (or main process step), Putting value adding elements in green, unavoidable wasteful steps in orange and wasteful steps in red allows you to quickly see where waste is built into your process also.
This stacked bar should be beneath the takt time line, if not the operator has too much work to complete within the cycle time and some of his work should be passed to the operators either before or after him depending on who has some spare capacity.
This analysis using your Takt time has the additional benefit of forcing you to look at the actual process to review how work is conducted. It helps you to improve actual processes and forces you to look at how you can remove or reduce the wasteful steps in your process.
Balancing Production for Variable Takt Times
If the demand for a product is highly variable or seasonal then there may be a need to balance a work cell to cope with varying levels of demand, this can be achieved by balancing the work elements to the number of operators based on the different required Takt times. So you would balance the Cell for 1 or 2 operators for lower demand times, 3 or 4 for normal production and 5 or 6 operators for peak production periods; each having a set of instructions defining the operations to be undertaken by each operator to achieve the required Takt time and output.
By providing the Takt time for each scenario you can use your Yamazumi planning board to balance the line efficiently for each demand rate and flex your manpower accordingly as with the diagrams below.
Using Takt Time to Balance Work FlowClick thumbnail to view full-size
Lean Tact time
Setting up production processes with no idea of your Takt time will result in poorly balanced production processes with people that are wither overworked or waiting for other processes. Using Takt time and Yamazumi analysis allows you to quickly see where the issues are within your organization and to balance the workload accordingly.
It also allows you to efficiently flex your workforce to cope with changes in demand as with the diagrams above. Why have three people working a work cell and passing time to just meet customer demand (as they will) when you can use the labor elsewhere in your processes where there is greater demand.
If you have any questions about Takt time or any other lean manufacturing tool please feel free to leave comments below.